The prior art has evolved a wide variety of multiple bit screwdrivers, some of which incorporate mechanisms for loading bits from a bit storage magazine directly into the screwdriver's chuck and for removing bits from the chuck and returning them to the magazine. For example, U.S. Pat. No. 1,579,498 Anderson, issued 6 Apr. 1926 provides a screwdriver type tool in which the bit storage magazine comprises a plurality of chambers spaced radially around the inner circumference of the screwdriver's handle. A cap on the end of the handle is rotated into alignment with a selected bit chamber. A “plunger pin” is then withdrawn through the cap, allowing the selected bit to drop into the space previously occupied by the plunger pin. The plunger pin is then pushed back through the cap, to force the selected bit through an apertured shaft which protrudes from the handles opposite end, until the tip of the bit extends through the bit chuck at the shaft's outward end.
Anderson's device has some disadvantages. For example, Anderson's device relies upon the force of gravity to move a bit from its storage chamber into the space evacuated by the plunger pin; or, to return a bit to an empty storage chamber. The force of gravity is also used to remove a bit from the chuck (i.e. the tool is held vertically and the plunger pin withdrawn, allowing the bit to fall out of the chuck and drop through the shaft into the space evacuated by the plunger pin). It is accordingly necessary for the user to orient and manipulate the tool between various horizontal and vertical positions in order to properly exploit the force of gravity as bits are loaded and unloaded. The present invention overcomes these disadvantages.